During the 06 year we will investigate increased accuracy of the new audio-video method of recording and interpreting Doppler examination data. We will investigate a new frequency ratio method of estimating % of stenosis of carotid arteries. Doppler imaging potential for diagnosis of femoral artery lesions will be studied. Visual spectral patterns for blood flow turbulence and non-stenotic plaquing will be cataloged. The usefulness of Infinite Gate Pulsed Doppler in measuring arterial diameters and volumetric flow will be investigated.